How to Separate Gold Plating From Copper

Gold plating refers to the activity of beautifying objects with a covering or a design of gold which may be in powder form. It is a method of depositing a thin layer of gold onto a surface of another different metal, mostly copper or silver. This is usually done by electrochemical or chemical means

1.Prepare a potassium-iodide solution which will be used to strip gold. Have distilled water, iodine and potassium iodide. Add iodine, potassium iodide and distilled water in the ratio of 1:4:10 in terms of weight. Sodium iodide-iodine solution can also be used as a substitute for the potassium iodide-iodine solution. The main function of iodine is to oxidize the gold plating, while iodide contributes to making the iodized gold soluble.

2.Add the potassium iodide into the distilled water and stir until both are completely dissolved.

3.Add the weighted iodine into the solution. This should be done only after the potassium iodide has been completely dissolved. However, during the addition of iodine, do not stir.

4.Immerse the gold-plated copper into the stripping solution until the gold plating has been removed completely. This should be done at temperatures of between 350 and 400 degrees Celsius.

5.Precipitate the gold that has been dissolved and removed by adding 30 percent hydroxylamine hydrochloride solution. This solution is usually neutralized by use of sodium hydroxide, and it is added up to the point where the solution turns from brown color to clear. Sodium hydroxide is a reducing agent especially in acidic environments. Hydroxylamine hydrochloride solution is usually used as a reducing agent in an alkaline environment to precipitate gold.

6.Add an excess amount of the reducing agent solution to ensure complete removal and precipitation of gold. This should be approximately a third of the initial added amount.

7.Remove the precipitated gold through filtration.

8.Regenerate the hydroxylamine hydrochloride solution by adding 30 percent hydrogen peroxide to every hundred milliliters of the stripping solution. This will assist in restoration of the stripping solution to its former strength.

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